The present invention relates to the field of transportation and distribution of gas cylinders, in both large and small quantities.
Pressurized cylinders have long been used for storage of specialized industrial gases. These cylinders are typically filled with gases such as oxygen, propane, acetylene, argon, nitrogen, or others. The cylinders are generally filled with the gas before delivery to a customer. After the gas is consumed, the cylinders are returned to the gas supply outlet, and replacement cylinders are delivered. The distribution of gases therefore involves repeated loading and unloading of filled or empty gas cylinders.
Sometimes, a user of industrial gases requires gas in large quantities. At other times, as is the case for many small welding shops, only one or two cylinders will supply the needs of the shop for a reasonably long time. It is therefore necessary to handle small numbers of gas cylinders. The effort involved in handling such small quantities is magnified when, as often happens, the user of industrial gases requires small quantities of each of several different types of gas.
The prior art has taught only one way of delivering loads of gas cylinders. A flatbed truck, i.e. a truck having a generally solid, flat surface, is loaded with a plurality of cylinders, the cylinders being tightly packed on the truck bed. Cylinders containing different types of gas are generally mixed together. The cylinders are then secured by a rope or chain extending across the bed of the truck. When a customer needs a type of gas which is found only in a cylinder which was packed onto the truck at the start of the loading process, all of the cylinders which were loaded subsequently must be moved, in order to gain access to the desired cylinder. After the desired cylinder has been removed, the cylinders which were moved to make way for the first cylinder must be then be returned to their previous positions.
It is clear that the process described above is cumbersome and inefficient, especially when used to deliver small numbers of cylinders, and to deliver small quantities of each of several gases. Much of the cost of the gases is attributable to the labor required in delivering them. The prior art method described above is clearly very labor intensive.
Few attempts have been made, in the prior art, to improve the process of transportation and distribution of gas cylinders. One such attempt is represented by U.S. Pat. No. 4,295,431, which shows a pallet for holding pressurized gas cylinders. By holding the cylinders in pallets, more than one cylinder may be handled at once. The pallet includes three vertical side walls, and an open side for loading and unloading cylinders from the pallet. Another patent dealing with transportation and distribution of gas cylinders is U.S. Pat. No. 3,993,344, which shows a plurality of pallets disposed on a flatbed truck.
Other examples of the prior art include U.S. Pat. No. 2,763,383, which shows apparatus for handling cylindrical containers, including gas containers; U.S. Pat. No. 4,325,669, showing a pallet loading and unloading system; U.S. Pat. No. 4,462,746, which shows apparatus for handling palletized loads; U.S. Pat. No. 3,734,315, which discloses another means for transporting palletized loads; and U.S. Pat. No. 4,165,806, showing another palletized distrubution system.
The present invention solves the problem of transporting and distributing varying quantities of gas cylinders, using a simple and economical structure, and requiring a minimum of labor. The invention provides a method and apparatus for delivering gas cylinders, either in entire pallet loads, or individually, without the expenditure of much time or effort.